The mechanical distribution of paper sheets is a necessary procedure to implement the communication procedures of modern business.
Collation is one distribution function, but sorting and distribution according to a program are also paper sheet handling problems. Hence, such equipment is improperly labeled a collator, unless that is its only capability.
The first step away from an operator walking around a table to place one sheet on each of several stacks, was the use of a vertical set of shelves. The operator placed a stack of each page on each shelf, and then withdrew one after the other in sequence to compile a "book".
Mechanical implementation has generally mimicked the first human system, by directing one sheet at a time to series of pockets until all of the one page has been placed. Then sheet two is likewise distributed. A program added to such a system will permit true distribution. Multiple copies into one pocket, single in another, and none to yet another.
The sheets are conveyed along a path. This conveyor aspect of sheet distribution is not difficult. But to cause the sheets to separate from the conveyor and go into a selected pocket is a source of potential problems. Paper often jams.